What is migration? Annually, millions of birds leave their southern wintering grounds in search of food and a place to raise a family. Guided by the stars, the change in sunlight, and the earth's magnetic field  following their ancient instincts  migratory birds make this epic northward journey every year. The biological urge that triggers migration causes birds to store up fat for the energy to make the trip. They battle exhaustion, predators, and storms to reach the breeding grounds. Once the young are fledged the remarkable trip is reversed.

Which birds migrate?

Not all birds migrate. Some species are permanent residents and live and breed in the same region. Some merely move about within a small area as food availability changes. Others migrate short distances. But some birds make migratory journeys that are nothing short of spectacular.

What path do they take?

The paths that migratory birds take often follow geographic features such as mountain ranges and river valleys. These paths may vary greatly from year to year and also by species. Although we often speak of routes and flyways, there is probably not a single square mile of the Earth's surface, excluding the polar ice caps, over which birds do not fly.

How far do migrants fly?

The title for distance is held by the Arctic Tern (below). This small bird makes its journey from the Antarctic to the Arctic annually, a trip of 11,000 miles each way.

The bobolink (below) is one of the top migrants in the Americas, covering 7,000 miles or more between the clover fields of Canada and the grasslands of Argentina.

Which birds make the trip nonstop?

Many migrants travel with a series of short flights and frequent stopovers. Others make longer flights. During fall migration, the Red Knot (below) may fly nonstop for 60 hours from the lower Arctic to the mudflats of New England, and then may continue its migration by flying nonstop to northern South America.

How fast do migrants fly?

The White-rumped Sandpiper (right), which migrates from Argentina to the Arctic, belongs to the group of birds that are among the fastest flyers. Some sandpipers have been clocked at more than 100 miles per hour.

How high do migrants fly?

Many birds have been seen from airplanes. Some birds migrating long distances over water may fly as high as 14,000 feet. The record holder is the Bar-headed Goose (below) (only an escaped bird in our region), once seen over the Himalayas at approximately 28,000 feet.